Method of Single-Cell Point-to-Multipoint Transmission

ABSTRACT

A method of single-cell point-to-multipoint (SCPTM) transmission for a network in a wireless communication system is disclosed. The method comprises performing a query procedure to obtain information associated with a number of mobile device interesting or receiving at least a SCPTM service, and determining to turn on/off data transmission for the at least a SCPTM service, turn on/off feedback procedure for the at least a SCPTM service according to the obtained information, or to provide the obtained information to a group communication service application server (GCS AS).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/109,061, filed on Jan. 29, 2015 and entitled “Method of queryprocedure for Single-Cell Point-to-Multipoint data transmission”, thecontents of which are incorporated herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method used in a communication devicein a wireless communication system, and more particularly, to a methodof single-cell point-to-multipoint transmission.

2. Description of the Prior Art

3GPP in Release 12 proposes single-cell point-to-multipoint (SCPTM)service to reuse the Multimedia Broadcast Multicast Service (MBMS)structure for critical communications, such as public safetyapplications and general commercial applications (e.g., utilitycompanies and railways). Note that, SCPTM service aims at providing MBMSsession established on a single cell for critical communications, whichis different to original MBMS design for the provision of media contentin a large per-planned area (i.e. MBSFN area), where MBMS session isestablished on a plurality of cells.

Please refer to FIG. 1, which illustrates a schematic diagram formapping between TMGI and G-RNTI for a SCPTM service. A user equipment(UE) could perform SCPTM reception either in idle mode or in connectedmode. The UE knows a Temporary Mobile Group Identity (TMGI) for thegroup of interest via User Service Guide (USG). The TMGI is used toidentify a SCPTM service. The eNB provides the mapping between G-RNTIand TMGI by single cell-multicast control channel (SC-MCCH). When theeNB provides the TMGI and G-RNTI mapping by SC-MCCH, the UE interestingSCPTM service could monitor the SC-MCCH to find the desired SCPTMservice's TMGI and the corresponding G-RNTI mapping. Once the UE findsthe desired SCPTM service's corresponding G-RNTI mapping, the UE couldget the desired SCPTM service's resource information by monitoringPhysical Downlink Control Channel (PDCCH) associate with thecorresponding G-RNTI. Then, the UE could get the desired SCPTM servicefrom Physical Downlink Shared Channel (PDSCH).

In addition, please refer to FIG. 2, which illustrates a schematicdiagram of a MBMS session life cycle for a SCPTM service according tothe prior art. In FIG. 2, a MBMS session life cycle includes “serviceannouncement”, “session start”, “MBMS notification”, “data transfer” and“session stop”. In a word, when a MBMS session for a SCPTM service isstarted, the MBMS session will start the data transfer until the sessionstop. However, this will reduce the radio efficiency over SCPTM servicebecause a cell has to continue data transmission of the MBMS session forthe SCPTM service even there are no interested UE in its coverage.

SUMMARY OF THE INVENTION

It is therefore an objective to provide a method of SCPTM datatransmission to solve the above problem.

The present invention discloses a method of single-cellpoint-to-multipoint (SCPTM) transmission for a network in a wirelesscommunication system. The method comprises performing a query procedureto obtain information associated with a number of mobile deviceinteresting or receiving at least a SCPTM service, and determining toturn on/off data transmission for the at least a SCPTM service, turnon/off feedback procedure for the at least a SCPTM service according tothe obtained information, or to provide the obtained information to agroup communication service application server (GCS AS).

The present invention discloses a method of single-cellpoint-to-multipoint (SCPTM) transmission for a mobile device in awireless communication system. The method comprises receiving a querymessage for reporting a receiving-service indication, from a network ofthe wireless communication system, and in response to the query message,sending the receiving-service indication to the network, wherein thereceiving-service indication includes a TMGI and a cell identity for aSCPTM service received by the mobile device.

The present invention discloses a method of single-cellpoint-to-multipoint (SCPTM) transmission for a mobile device in awireless communication system. The method comprises monitoring a messageincluding mapping information between at least a temporary mobile groupidentity (TMGI) and at least a group radio network temporary identity(G-RNTI), determining whether a SCPTM service is started or activatedaccording to whether one of the at least a TMGI corresponding to theSCPTM service is mapped to a G-RNTI, and performing a query procedure tostart data transmission for the SCPTM service when the SCPTM service isnot started or activated.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram for TMGI and G-RNTI mapping according tothe prior art.

FIG. 2 is a schematic diagram of a MBMS session life cycle according tothe prior art.

FIG. 3 is a schematic diagram of a wireless communication system.

FIG. 4 is a schematic diagram of an exemplary communication device.

FIG. 5 is a flowchart of an exemplary process according to the presentdisclosure.

FIG. 6 is a schematic diagram of a life cycle of a MBMS session for theSCPTM transmission according to the present disclosure.

FIGS. 7-10 are schematic diagrams of an eNB query procedure.

FIG. 11 is a schematic diagram of UE behavior in an eNB query procedure.

FIG. 12 is a flowchart of an exemplary process according to the presentdisclosure.

FIG. 13 is a schematic diagram of a SC-MCCH message.

FIGS. 14-15 are schematic diagrams of an UE query procedure.

FIGS. 16-17 are schematic diagrams of eNB behavior in an UE queryprocedure.

DETAILED DESCRIPTION

Please refer to FIG. 3, which is a schematic diagram of a wirelesscommunication system. The wireless communication system is a LTE systemor other mobile communication systems, and is composed of a groupcommunication service application server (GCS AP), Broadcast-MulticastService Centre (BM-SC), MBMS Gateway (MBMS-GW), Mobility ManagementEntity (MME), MBMS coordination entity (MCE), eNBs and user equipments(UEs). Note that, the GCS AP is responsible for providing data tomultiple UEs at the same time by MBMS transmission or single-cellpoint-to-multipoint (SCPTM) transmission. The BM-SC is used for MBMScontrol, such as MBMS service announcement and MBMS session start. TheMBMS GW is used for establishment of MBMS session with eNB by MME. Inaddition, the MCE aims at choose between MBMS and SCPTM transmission.

FIG. 4 is a schematic diagram of an exemplary communication device 40.The communication device 40 can be the UE or eNB shown in FIG. 3. Thecommunication device 40 may include a processing means 400 such as amicroprocessor or Application Specific Integrated Circuit (ASIC), astorage unit 410 and a communication interfacing unit 420. The storageunit 410 may be any data storage device that can store program code 414,for access by the processing means 400. Examples of the storage unit 410include but are not limited to a subscriber identity module (SIM),read-only memory (ROM), flash memory, random-access memory (RAM),CD-ROMs, magnetic tape, hard disk, and optical data storage device. Thecommunication interfacing unit 420 is preferably a radio transceiver andcan exchange wireless signals with a network node (i.e. an eNB) or acommunication device (i.e. an UE) according to processing results of theprocessing means 400.

Please refer to FIG. 5, which is a flowchart of a process 50 accordingto an example of the present disclosure. The process 50 is utilized inthe eNB of FIG. 3 for SCPTM transmission. The process 50 may be compiledinto a program code 414 to be stored in the storage unit 410, and mayinclude the following steps:

Step 500: Start.

Step 510: Perform a query procedure to obtain information associatedwith a number of UE interesting or receiving at least a SCPTM service.

Step 520: Determine to turn on/off data transmission for the at least aSCPTM service, turn on/off feedback procedure for the at least a SCPTMservice according to the obtained information, or to provide theobtained information to a GCS AS.

Step 530: End.

According to the process 50, the eNB performs the query procedure toinvestigate how many interested UE or how many UE receives the SCPTMservice. As a result, the eNB can dynamically control (e.g. turn off orturn on) the data transmission for the SCPTM service or the feedbackmechanism for the SCPTM service. Or, the eNB can bring the investigationto the GCS AS to determine whether to use the MBMS transmission for theSCPTM service. With such manner, radio efficiency is improved in theSCPTM service.

In addition, the present invention proposes new statuses for the SCPTMservice. A SCPTM service is called un-activated SCPTM service when aMBMS session for the SCPTM service is started but its data transmissionis turned off by a cell. The SCPTM service is called activated SCPTMservice when a MBMS session for the SCPTM service is started and itsdata transmission is turned on by a cell.

In detail, by querying interested UE number or receiving SCTPM serviceUE number, the eNB decides whether to turn off the data transmission foran activated SCPTM service. For example, the eNB may decides to turn offthe data transmission for an activated SCPTM service if the number ofinterested UE or the number of receiving SCPTM service UE is below athreshold (ex:4). Otherwise, the eNB continues the data transmission forthe activated SCPTM service. Moreover, the eNB may report relatedinformation to the GCS AS. For example, if there is no receiving SCPTMservice UE, the eNB may inform this information (i.e. interested UEnumber or the receiving SCPTM service UE number) to GCS AS or if thenumber of receiving SCPTM service UE is below a threshold. Besides, theeNB could also decide whether turn on the feedback procedure. Forexample, the eNB may decides to turn on the feedback procedure for aSCPTM service if the number of interested UE or the number of receivingSCPTM service UE is below a threshold. Once the feedback mechanism turnson, the UE could feedback the SCPTM data receiving status to help eNB todecide better transmission method (e.g., better modulation and codingset).

Please refer to FIG. 6, which illustrates a life cycle of a MBMS sessionfor the SCPTM transmission. Compared to the MBMS session life cycleshown in FIG. 2, the MBMS session life cycle shown in FIG. 6 furtherincludes a step of “data does not transfer”, namely data transmission ofthe MBMS session for the SCPTM service can be turned off and turned onby the eNB according to the number of UE interesting or receiving theSCPTM service, which is obtained via the query procedure.

The present invention proposes several alternative methods for queryinginterested UE number or receiving SCTPM service UE number. In anembodiment, if an eNB wants to query the interested UE number for anactivated SCPTM service, it could just provide un-activated SCPTMservice information to UEs in the serving area. In detail, the eNB stopsallocating or mapping the G-RNTI for the target activated SCPTM servicein SC-MCCH of a cell. However, the eNB still uses the G-RNTI in PDCCH toindicate the SCPTM service in PDSCH in order not to affect the activatedSCPTM service operation. If any UE is interested to the target activatedSCPTM service, it will follow a UE query procedure to send the queryindication. In this way, the eNB could investigate whether the UE isinterested in an activated SCPTM service in a cell. Detailed operationfor the UE query procedure is described in this article later on.

Please refer to FIG. 7, which illustrates an example for querying UEnumber interesting in an activated SCPTM service. In this example, if aneNB wants to investigate that is any UE interested to the activatedSCPTM service with TMGI#3, it will stop allocating or mapping G-RNTI#cto TMGI190 3 in SC-MCCH. As a result, the UE considers the SCPTM servicecorresponding to TMGI190 3 is an un-activated SCPTM service. Then, ifany UE is interested to the SCPTM service corresponding to TMGI190 3, itwill perform the UE query procedure to turn on data transmission for theSCPTM service. However, in order not to affect the activated SCPTMservice (namely not to affect the current receiving SCPTM serviceusers), the eNB still allocates the G-RNTI#c in PDSCH to indicate theSCTPM service in PDSCH.

On the other hand, if an eNB wants to query the UE number receiving aSCPTM service, the eNB sends a query message to the UE. Please refer toFIG. 8, which illustrates a first example of the query message. In FIG.8, the eNB carries query information in additional information in PDSCHfor each SCPTM service. The query information is used to request andcontrol the UE to report a receiving-service indication. By reception ofthe receiving-service indications from the UEs, the eNB could obtain theinformation of receiving SCPTM service UE number. The receiving-serviceindication may include information of the corresponding TMGI and a cellidentity for the SCPTM service.

For receiving-service indication reporting, a connected mode UE may usea UL resource requested by normal resource request procedure to send thereceiving-service indication. On the other hand, an idle mode UE may usea UL resource requested by random access (RA) procedure to send thereceiving-service indication. For example, the UE could perform the RAat the original PRACH (Physical Random Access Channel) resource or at aspecific resource indicated by the query information in the additionalinformation. The specific resource could be a dedicated resource usedfor RA procedure. In addition, the idle mode UE could also use theRRCConnectionRequest message to carry the receiving-service indicationand return to idle mode after sending the receiving-service indication.

In other embodiments, please refer to FIG. 9, which illustrates a secondexample of the query message. The eNB uses a request indication and areporting timer in the query information to request and control a UE toreport the receiving-service indication. If the UE receives the requestindication and the reporting timer from the query information of itsreceiving SCPTM service, it may report the receiving-service indicationto the eNB during the reporting time. Therefore, the eNB could decidewhether any UE receives the SCPTM service or the roughly number of UEreceives the SCPTM service by the number of receiving-serviceindication.

In addition, there may be lots of receiving SCPTM service UEs report thereceiving-service indications during the reporting time. This may causeresource congestion for reporting the receiving-service indications.Please refer to FIG. 10, which illustrates a third example of the querymessage. In FIG. 10, the eNB could use the query factor in queryinformation to request and control the receiving-service indicationreporting. Once a UE receives the query factor from the queryinformation of its receiving SCPTM service, the UE will report thereceiving-service indication if it satisfies the reporting condition.Besides, in order to distribute UE reporting the receiving-serviceindication, the eNB uses the query factor to control the reportingcondition. The query factor could be a real number between 1 and 10. Thequery factor may be continually appeared in query information. Theduration of query information which continues carrying the query factoris called query period.

Detailed operation for the query factor is described as following. Withquery factor in query information, if the eNB want to know is there anyUE receiving the SCPTM service in a cell or eNB wants to know whetherthe number of UE receiving the SCPTM service exceed the threshold. TheeNB could control the query period to reduce the un-necessary reporting.For example, once eNB receives the receiving-service indication exceedthe threshold, the eNB stop the query period by stopping carrying thequery factor in additional information. In this way, other receivingSCPTM service UE will not report the receiving-service indication.

In addition, with query factor, the eNB could alsodistribute/concentrate the reporting number based on the currentresource loading. For example, if the cell loading is heavy, eNB couldassign the query factor to be 1, 2, 3 . . . and 10 respectively in theadditional information to distribute the reporting number. If the cellloading is light, eNB could assign the query factor to be 5 and 10respectively in the additional information to concentrate the reportingnumber.

Please refer to FIG. 11, which illustrates a UE behavior in the eNBquery procedure. In each query period, the UE will only report thereceiving-service indication once. When UE receives the query factorfrom query information in the receiving SCPTM service, the UE may randomselect a number between 0 and 9 if the UE does not report thereceiving-service indication in this query period. If the randomselected number is smaller than the query factor, it will report thereceiving-service indication. Otherwise, the UE continues receiving theSCPTM service and not report the receiving-service indication.

Please refer to FIG. 12, which is a flowchart of a process 120 accordingto an example of the present disclosure. The process 120 is utilized inthe UE of FIG. 3 for SCPTM transmission. The process 120 may be compiledinto a program code 414 to be stored in the storage unit 410, and mayinclude the following steps:

Step 1200: Start.

Step 1210: Monitor a message including mapping information between atleast a TMGI and at least a G-RNTI.

Step 1220: Determine whether a SCPTM service is started/activatedaccording to whether one of the at least a TMGI corresponding to theSCPTM service is mapped to a G-RNTI.

Step 1230: Perform a query procedure to start/turn on data transmissionfor the SCPTM service when the SCPTM service is not started/activated.

Step 1240: End.

According to process 120, the UE could use query procedure to remind theeNB to turn on the data transmission for the desired SCPTM service.

In addition, in the UE query procedure, the UE could use a queryindication to remind eNB to turn on the data transmission for thedesired un-activated SCPTM service. The query indication may carry theTMGI for the desired un-activated SCPTM service and it may also includethe desired un-activated SCPTM service's cell identity in carrieraggregation (CA) scenarios. As a result, the query indication could letthe eNB realize which un-activated SCPTM service is desired.

A connected mode UE could use normal UL resource request procedure torequest UL resource to send the query indication. An idle mode UE coulduse random access (RA) procedure to request UL resource to send thequery indication. The idle mode UE could use the RRCConnectionRequestmessage to carry the query indication. After sending query indication,the UE could continue monitoring a SC-MCCH message for TMGI and G-RNTImapping information. On the other hand, the eNB could decide whetherturn on/off data transmission for a SCPTM service based on the receivedquery indication number. For example, eNB may decide to turn on the datatransmission for an un-activated SCPTM service, if eNB receives thenumber of query indication is bigger than a threshold (ex: 4).

In an embodiment, a cell provides the un-activated SCPTM serviceinformation to a UE. Please refer to FIG. 13, which illustrates anexample for a SC-MCCH message. The SC-MCCH message includes a SCPTMservice list carrying mapping information between TMGI and G-RNTI. Asshown in FIG. 13, the SCPTM services associate with TMGI 190 1-#3 mappedto G-RNTI #a-#c are considered as activated SCPTM services, but theSCPTM services associate with TMGI #4 and #5 mapped to no G-RNTI areconsidered as un-activated SCPTM services. In a word, an un-activatedSCPTM service does not have a G-RNTI mapping to a TMGI in the SCPTMservice list. In other words, based on the SC-MCCH message, the UE couldunderstand whether data transmission for a SCPTM service is started ornot. Detailed operation for the UE query procedure is described asfollowing.

Please refer to FIG. 14, which illustrates a flow chart of a UE queryprocedure with the un-activated SCPTM service information. When an UEneeds a SCPTM service, the UE could monitor the SC-MCCH message whichcarries the TMGI and G-RNTI mapping to find whether the desired SCPTMservice session is started. If UE find the desired SCPTM service is notstarted (for example the TMGI #x is not in the SCPTM service list), itwill request the GCS AS to start the SCPTM service session and thenmonitoring the SCPTM service list. If UE find the TMGI #x in the SCPTMservice list, it will further verify whether the desired SCPTM serviceis activated or not by checking the corresponding G-RNTI mapping. If thedesired SCPTM service is activated (for example the TMGI #x has acorresponding G-RNTI mapping), the UE will monitor PDCCH by thecorresponding G-RNTI. Once the desired SCPTM service isn't activated(for example the TMGI #x doesn't have a corresponding G-RNTI mapping),the UE will send the query indication to eNB for the desired SCPTMservice. After sending the query indication, UE will continue monitoringthe SCPTM service list.

In other embodiments, please refer to FIG. 15, which illustrates a flowchart of a UE query procedure without the un-activated SCPTM serviceinformation. In FIG. 15, the UE sends the query indication if UE desiredSCPTM service is not in SCPTM service list. After sending the queryindication, if UE receives a response message from the eNB, the UE mayrequest the GCS AS to start the desired SCPTM based on the responsemessage. Otherwise, the UE will continue monitoring the SCPTM servicelist. The response message from the eNB could indicate the reason whycell cannot start the SCPTM data transmission. The reason that eNBcannot start the SCPTM data transmission could be that the SCPTM serviceis not started by the GCS AS yet or the cell cannot request GCS AS tostart the SCPTM service.

Please refer to FIG. 16-17 for eNB behavior in the UE query procedure.As shown in FIG. 16, if the desired SCPTM service is started, the eNBwill turn on the data transmission for the desired SCPTM service andprovide the corresponding G-RNTI mapping. However, if the desired SCPTMservice is not started, the eNB could request GCS AS to start the SCPTMservice, the eNB will send the SCPTM service request to GCS AS. On theother hand, as shown in FIG. 17, if the desired SCPTM service is notstarted, the eNB responses to UE that the desired SCPTM service is notstarted.

The abovementioned steps of the processes including suggested steps canbe realized by means that could be a hardware, a firmware known as acombination of a hardware device and computer instructions and data thatreside as read-only software on the hardware device or an electronicsystem. Examples of hardware can include analog, digital and mixedcircuits known as microcircuit, microchip, or silicon chip. Examples ofthe electronic system can include a system on chip (SOC), system inpackage (SiP), a computer on module (COM) and the communication device40.

In conclusion, the present invention provides an eNB query procedure forgetting the referencing information to decide how to dynamic controldata transmission scheme for a SCPTM service, so as to enhance thedynamic control data transmission scheme for a SCPTM service. Inaddition, the present provides a UE query procedure to turn on or starta desired or interested SCPTM service (i.e. an un-activated SCPTMservice or not started SCPTM service).

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method of single-cell point-to-multipoint(SCPTM) transmission for a network in a wireless communication system,the method comprising: performing a query procedure to obtaininformation associated with a number of mobile device interesting orreceiving at least a SCPTM service; and determining to turn on/off datatransmission for at least a SCPTM service, turn on/off feedbackprocedure for the at least a SCPTM service according to the obtainedinformation, or to provide the obtained information to a groupcommunication service application server (GCS AS).
 2. The method ofclaim 1, wherein performing the query procedure to obtain informationassociated with the number of mobile device receiving at least a SCPTMservice comprises: sending a query message for requesting mobile devicesin a serving area of a network of the wireless communication system toreport receiving-service indications, to the mobile devices; wherein thereceiving-service indications each include a temporary mobile groupidentity (TMGI) corresponding to the SCPTM service and a networkidentity.
 3. The method of claim 2, further comprising: receiving thereceiving-service indications to obtaining information associated withthe number of mobile devices receiving the SCPTM service, from themobile devices.
 4. The method of claim 2, wherein the query messageincludes an uplink resource for mobile devices in an radio link resourceidle mode to report the receiving-service indications.
 5. The method ofclaim 2, wherein the query message includes control information for thereceiving-service indication reporting, and the control information isassociated with a reporting timer for a duration of reporting thereceiving-service indications.
 6. The method of claim 2, wherein thequery message is sent on Physical Downlink Shared Channel (PDSCH) forthe SCPTM service.
 7. The method of claim 2, wherein the query messageincludes control information associated with a query factor for themobile device to determine whether to report the receiving-serviceindication in a query period, wherein the query period starts when thequery factor is configured in the query message and stops when the queryfactor is not successively configured in the message.
 8. The method ofclaim 1, wherein determining to turn on/off the data transmission forthe at least a SCPTM service, turn on/off feedback procedure for the atleast a SCPTM service according to the obtained information, or toprovide the obtained information to the GCS AS comprises: determining toturn off the data transmission for the at least a SCPTM service when thenumber of mobile device interesting or receiving the SCPTM is less thana threshold; and determining to turn on the feedback procedure for theat least a SCPTM service when the number of mobile device interesting orreceiving the SCPTM service is less than a threshold.
 9. The method ofclaim 1, wherein performing the query procedure to obtain informationassociated with the number of mobile device interesting at least a SCPTMservice comprises: stopping mapping a TMGI corresponding to a ongoingSCPTM service to a G-RNI.
 10. A method of single-cellpoint-to-multipoint (SCPTM) transmission for a mobile device in awireless communication system, the method comprising: receiving a SCPTMservice and a query message for requesting the mobile device to report areceiving-service indication for the SCPTM service, from a network ofthe wireless communication system; and in response to the query message,sending the receiving-service indication to the network, wherein thereceiving-service indication includes a TMGI and a cell identity for theSCPTM service received by the mobile device.
 11. The method of claim 10,wherein sending the receiving-service indication to the networkcomprises: sending the receiving-service indication with an uplinkresource request procedure when the mobile device is in a radio resourcecontrol (RRC) connected mode; or sending the receiving-serviceindication with a random access procedure to request an uplink resourcefor the receiving-service indication when the mobile device is in a RRCidle mode; or sending the receiving-service indication with a randomaccess procedure performed at a resource indicated by a query message torequest an uplink resource for the receiving-service indication when themobile device is in a RRC idle mode.
 12. The method of claim 10, whereinthe query message includes control information associated with areporting timer for a duration of reporting the receiving-serviceindication report.
 13. The method of claim 10, wherein the query messageincludes control information associated with a query factor for themobile to determine whether to report the receiving-service indicationin a query period, wherein the query period starts when the query factoris configured in the query message and stops when the query factor isnot successively configured in the message.
 14. The method of claim 13,further comprising: determining that the mobile device have ever reportthe receiving-service indication in the query period; randomly selects anumber when the mobile device does not report the receiving-serviceindication in the query period; determining whether the selected numberis smaller than the query factor; and reporting the receiving-serviceindication if the selected number is smaller than the query factor. 15.A method of single-cell point-to-multipoint (SCPTM) transmission for amobile device in a wireless communication system, the method comprising:monitoring a message including mapping information between at least atemporary mobile group identity (TMGI) and at least a group radionetwork temporary identity (G-RNTI); determining whether a SCPTM serviceis started or activated according to whether one of the at least a TMGIcorresponding to the SCPTM service is mapped to a G-RNTI; and performinga query procedure to start or turn on data transmission for the SCPTMservice when the SCPTM service is not started or not activated.
 16. Themethod of claim 15, wherein determining whether the SCPTM service isstarted or activated according to whether one of the at least a TMGIcorresponding to the SCPTM service is mapped to the G-RNTI comprising:determining the SCPTM service is started when one of the at least a TMGIcorresponding to the SCPTM service is mapped to the G-RNTI; anddetermining the SCPTM service is not activated when one of the at leasta TMGI corresponding to the SCPTM service is not mapped to the G-RNTI.17. The method of claim 16, further comprising: determining whether datatransmission for the SCPTM service is activated when the SCPTM serviceis started.
 18. The method of claim 17, further comprising: performingthe query procedure to turn on the data transmission for the SCPTMservice when the SCPTM service is started but the data transmission forthe SCPTM service is not activated.
 19. The method of claim 17, furthercomprising: receiving the data transmission for the SCPTM service withthe mapped G-RNTI when the SCPTM service is started and the datatransmission of the MBMS session for the SCPTM service is activated. 20.The method of claim 15, wherein performing the query procedure to startthe data transmission for the SCPTM service when the SCPTM service isnot started comprises: sending a query indication to a network of thewireless communication system, wherein the query indication includes theTMGI corresponding to the SCPTM service or a cell identity providing theSCPTM service.
 21. The method of claim 18, wherein performing the queryprocedure to turn on the data transmission for the SCPTM service whenthe SCPTM is started but the data transmission for the SCPTM service isnot activated comprises: sending a query indication to a network of thewireless communication system, wherein the query indication includes theTMGI corresponding to the SCPTM service or a cell identity providing theSCPTM service.
 22. The method of claim 20, further comprising: receivinga response indicating that the SCPTM service is not started, from thenetwork in response to the query indication.
 23. The method of claim 15,further comprising: receiving data transmission for the SCPTM servicewith the mapped G-RNTI when the SCPTM service is started.
 24. The methodof claim 20, wherein sending the query indication to the networkcomprises: sending the query indication with an uplink resource requestprocedure when the mobile device is in a radio resource control (RRC)connected mode; or sending the query indication with a random accessprocedure to request an uplink resource for the query indicationtransmission when the mobile device is in a RRC idle mode.
 25. Themethod of claim 21, wherein sending the query indication to the networkcomprises: sending the query indication with an uplink resource requestprocedure when the mobile device is in a radio resource control (RRC)connected mode; or sending the query indication with a random accessprocedure to request an uplink resource for the query indicationtransmission when the mobile device is in a RRC idle mode.